1. Todays Agenda 1. Stability Problems in negative Feedback
Transfer Function of the Feedback Amplifier
The Nyquist Plot
Effect Of Feedback On The Amplifier Poles
STABILITY STUDY USING BODE PLOTS
2. Analogue IC leading to op-amp
3. Introduction to filters.

2. Highlights
2.3.5 Advantages and Disadvantages of negative feedback

3. THE STABILITY PROBLEM Transfer Function of the Feedback Amplifier
The Nyquist Plot
Effect Of Feedback On The Amplifier Poles
STABILITY STUDY USING BODE PLOTS

4. Stability

5. Relationship between pole location and transient response.

6. Transfer Function of the Feedback Amplifier

7. The Nyquist Plot

9. Stable
The roots are at s=-5.5 and s=-0.24±2.88j so the system is stable

10. Margin-Stable
The roots are at s=-6 and s=±3.32j so the system is marginally stable, as expected.

11. Un-Stable
The roots are at s=-7.5 and s=+0.75±4.64j so the system is unstable, as expected.

12. Relationship between pole location and transient response.

14. Stability using bode plot

15. Analogue IC leading to op-amp

16. One-Stage Op
Amps 3

17. One-Stage Op Amp in Unity Gain
Configuration 4

18. Cascode Op
Amps 5

19. Unity
Gain
One
Stage
Cascode 6

20. Folded
Cascode Op
Amps
EECE488 Set 7 - Opamp Design 7

21. Single-Ended
Output
Cascode Op
Amps 13

22. Output
Impedance
Enhancement 15

23. Active FIlters
January 2004
ENGI 242/ELEC 222
Active Filters